How Your Brain Adjusts To Your Second Kid Is Quietly Miraculous

Last week, some friends and I started talking about what was harder — going from zero to one child, one to two children, or two to three children. It was an interesting question because we all agreed that becoming a mom for the first time shook up our lives the most. But, when it came to what made subsequent pregnancies difficult, we had varying opinions about what was to blame. Walking away from that conversation, I found myself thinking how pregnancy changes the brain.

The truth was, what made my second pregnancy so different from my first was the fact that I had changed so much. I was struggling more with exhaustion, my mental health, and even my physical health. Had my second pregnancy changed my brain? Or is all of this fogginess and forgetfulness just a part of getting older, adding more responsibilities, and dealing with outside stressors?

Pregnancy & Brain Changes

Here's the deal, we already know that pregnancy changes the brain. Specifically, research has found noteworthy differences between brains pre-pregnancy and post-pregnancy. One study published in Nature Neuroscience in 2017 actually noted grey matter shrinkage in pregnant women that lasted for up to two years after they gave birth. This study took MRIs of the brains of women before becoming pregnant, while pregnant, and two years after giving birth. For a consistent comparison, they also scanned the brains of men and women who were not parents and noted no significant brain changes in this group.

Researchers found that new mothers were experiencing grey matter shrinkage in their brains that lasted up to two years, suggesting specialization of brain function. The researchers conducting this study also noted that the women in this study experienced this shrinkage in varying amounts and that there seemed to be a link between greater loss of grey matter and better bonding between mother and baby.

It’s worth noting that this is the first study that has published these kinds of results, so further research needs to be done before parents can really interpret what this research means for them. Additionally, the researchers noted that their study didn’t find any change in cognitive abilities. So, while you might feel like you're experiencing pregnancy brain, it hasn’t been proven that these brain changes are causing you to forget milk at the grocery store or get tongue tied during work conversations.

There are other brain changes pregnant mothers experience. We know that hormones play a huge role in pregnancy, keeping baby and mom healthy, but they also affect the brain. Specifically, the hormones oxytocin and prolactin encourage a strong mother-baby bond, in addition to playing a role in milk production.

Some suspect these changes are related to pruning, that the brain changes in a way to eliminates unnecessary grey matter so we can be more adaptable, more ready for what the future of motherhood has in story. I like to think that is true, at least over the theory that us moms are losing cognitive abilities!

How Your Brain Changes After Your Second Kid

If first-time mothers experience a noticeable amount of ~neuroplasticity~ during pregnancy, what does that mean for mothers who are pregnant for the second time? It is certainly an interesting question. I’ve been pregnant three times now and each time my feet have grown by half a size — has my brain been shrinking each time, too?

The truth is, we don’t really know. According to Dr. G. Thomas Ruiz, OB-GYN Lead at MemorialCare Orange Coast Medical Center in Fountain Valley, California, there is no published literature examining brain changes in second-time moms. If it is true that the brain changes more or less the second time around, it is still important to remember that researchers haven’t established a link between brain changes caused by pregnancy and decreased cognitive abilities.

"Other studies haven't been able to demonstrate a change in IQ or overall cognitive ability," he says.

When you're single, you've got one lane. Then you get married, and you've got two lanes... Then you have a kid and your two lane road is now a highway. When you have a second kid... you're adding lanes to your highway.

Outside of grey matter shrinkage, we know that moms might be more at risk for prenatal depression during their second pregnancy if they were diagnosed with postpartum depression after their first pregnancy. Symptoms of depression are often more abstract than feeling down. Many individuals with depression report fogginess, forgetfulness, and changes in their sleep patterns.

Most obvious, perhaps, is the issue of added responsibility. The task of simply thinking about another human being is enough to overwhelm any mom.

Dr. Catherine Birndof, a psychiatrist, and co-founder and medical director of the Motherhood Center of New York, as well as the co-author of upcoming book What No One Tells You: A Guide to Emotions from Pregnancy to Motherhood, uses an analogy to create a picture of what is going on in the brain.

"When you're single, you've got one lane. Then you get married, and you've got two lanes," she says. "Then you have a kid and your two lane road is now a highway. When you have a second kid... you're adding lanes to your highway."

The highway in this analogy is the brain. For mothers of multiple children, this means their brain is always paying attention to those added lanes and the responsibilities that come with it, whether or not we're aware of it. Even when we're not with our child, somewhere in the back of our mind, we're wondering if they're OK, thinking about what they need, or recalling something they did or said.

"Even though you're sitting there talking to someone, in your mind, all these other things are going on," she explains further. "Once you have a child, you're never alone again."


According to Ruiz, being overtired and overwhelmed could be to blame when mothers feel different during the second pregnancy.

All mothers have a lot on their plate, but learning the balancing act of caring for a child while growing a child is next level exhaustion. One study, published in the journal Parenting in 2007 tried to determine if motherhood gets hard or easier the second time around. It was interesting to read the results because the answer was basically it depends. While it seemed the responsibilities in the household had stabilized, compared with the dramatic increase after the birth of a first child, many moms were experiencing stress in their relationship and that was impacting their experience as a second-time mom.

So, what’s a second-time mom to do when she’s feeling out of sorts?

Birndorf suggests that mothers start with a simple acknowledgement that their life has changed and it takes time to adjust. The good news? We will adjust.

"Our brain is plastic enough, we know our brains grow as we learn," she says. "I think they get, in some ways, more whole. Our brains are forced to do more and do better."

Additionally, Birndorf recommends a habit she has personally employed to remain focused on her work when she is away from her children — creating boundaries in your work life. For many this likely means making sure your sitter or partner knows how to reach you in the case of an emergency and then putting your phone away. Until you're ready to take a break, ignore text messages and the urge to check in so you can devote more brain power to the task at hand.

Lastly, simple steps like reducing environmental stress could help you to function more like yourself as you adjust to your new role. If your sleep is suffering, Ruiz stresses the importance of finding ways to get more rest. If you have outside stressors, or your responsibilities at home or work have changed, your circumstances might be to blame for forgetfulness and brain fog. Work with your partner or reach out to your family for help to adjust your lifestyle to allow for a little extra downtime and rest if possible.

If you have any concern that what you are experiencing is out of the ordinary, talk to your OB-GYN or midwife. They can screen you for perinatal mood and anxiety disorders and help you develop a plan for feeling more like yourself as you finish your pregnancy and move into postpartum with your second child.

If you or someone you know is experiencing depression or anxiety during pregnancy, or in the postpartum period, contact the Postpartum Health Alliance warmline at (888) 724-7240, or Postpartum Support International at (800) 944-4773. If you are thinking of harming yourself or your baby, get help right away by calling the National Suicide Prevention Lifeline at 1-800-273-8255, or dialing 911. For more resources, you can visit Postpartum Support International.